Apparatus and methods for performing brain surgery

Abstract

Less invasive surgical techniques for performing brain surgery are disclosed in which a dilating obturator and cannula assembly is inserted into brain tissue until the obturator tip and cannula are adjacent to the target tissue. The obturator is removed and surgery is performed through the cannula. In preferred embodiments the obturator and cannula are placed using image guidance techniques and systems to coordinate placement with pre-operative surgical planning. A stylet with associated image guidance may be inserted prior to insertion of the obturator and cannula assembly to guide insertion of the obturator and cannula assembly. Surgery preferably is performed using an endoscope partially inserted into the cannula with an image of the target tissue projected onto a monitor. Dilating obturator structures having a rounded or semi-spherical tip and/or an optical window for visualizing brain tissue during expansion are contemplated.

What is claimed is: 
     
       1. A method of performing brain surgery comprising:
 identifying target tissue located within a brain; 
 accessing the brain through an opening formed through a skull; 
 advancing a blunt dilating obturator having a shaft portion and an optically transparent tip at a distal end thereof into the brain over a stylet with a cannula mounted over the shaft portion to atraumatically dilate brain tissue while visualizing brain tissue through the optically transparent tip until the blunt dilating obturator is positioned adjacent the target tissue, wherein the stylet is placed into brain tissue under image guidance; and 
 removing the blunt dilating obturator leaving the cannula in place to provide access to the target tissue. 
 
     
     
       2. The method of  claim 1  wherein advancing the blunt dilating obturator and the cannula further includes atraumatically spreading brain tissue until the brain tissue surrounds the cannula. 
     
     
       3. The method of  claim 1  further including performing surgery on the target tissue through the cannula. 
     
     
       4. The method of  claim 3  further including inserting an endoscope into the cannula and performing surgery on the target tissue while visualizing the target tissue on a monitor. 
     
     
       5. The method of  claim 3  further including removing the cannula from the brain after performing surgery. 
     
     
       6. The method of  claim 3  further including monitoring brain function during surgery. 
     
     
       7. The method of  claim 1  further including breaking up and removing the target tissue through the cannula. 
     
     
       8. The method of  claim 1  further including providing a transparent cannula and viewing brain tissue through a wall of the cannula. 
     
     
       9. The method of  claim 1  wherein advancing the blunt dilating obturator until the blunt dilating obturator is positioned adjacent target tissue further includes advancing the blunt dilating obturator under image guidance. 
     
     
       10. The method of  claim 1  wherein advancing the blunt obturator and the cannula further includes providing the cannula with a cannula diameter of from about 10 mm to 15 mm and a cannula length of from about 2 cm to 6 cm.